Collapsible Layered Cushion

ABSTRACT

A layered cushion that may be fully disassembled for easy cleaning is disclosed herein. The sleep system is durable and fire retardant. The layered cushion may include a foam layer, a layer of void cells, and a cover. The foam permits fluids to move freely there through and contours to a user&#39;s body to maximize comfort and reduce interface pressure. The reticulated foam layer resists compression set and thermosetting. The layer of void cells also permits fluids to move freely there through and provide additional support to the user&#39;s body. The individual void cells of the void cell layer are perforated to allow the transmission of fluids there through. The cover couples the other layers together to form the layered cushion and prevents the layers from deteriorating. The cover is removable to permit cleaning each of the layers independently.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims benefit of priority to U.S. ProvisionalPatent Application No. 61/494,089, entitled “Washable Layered SleepSystem” and filed on Jun. 7, 2011, which is specifically incorporated byreference herein for all that it discloses or teaches. The presentapplication is further a continuation of International Application No.PCT/US2012/041306, entitled “Washable Layered Cushion” and filed on Jun.7, 2012, which is also specifically incorporated by reference herein forall that it discloses or teaches.

BACKGROUND

Mattresses are used in a wide variety of environments, such as in thehome, in hotels, in hospitals, in sport facilities, in securityfacilities, in emergency stations, during camping, and for militaryapplications. The mattresses provide comfort and impact protection to auser. Additionally, some mattresses may be portable and provide abarrier between the user's body and one or more objects that wouldotherwise impinge on the user's body in a variety of settings.Similarly, various cushions provide similar benefits to a user as aseating surface or lining of a protective device (e.g., a helmet or bodypads).

A variety of structures and materials may be used to make a mattress orother padding. For example, a pocketed spring mattress may contain anarray of close-coupled metal springs that cushion the user's body from abed frame. Additionally, an array of close-coupled closed-cell airand/or water chambers may be used, for example, in air and watermattresses. Further examples include convoluted open or closed cellpolyurethane foam, latex foam, and inversely convoluted foam.

However, conventional cushions, particularly mattresses in camping,military, and hospital applications, are difficult to clean betweenuses, and contaminants often accelerate the deterioration of suchmattresses. The cushions often retain fluids and trap particles or otherforeign objects. Further, many portable or reusable cushions aredesigned to maximize transportability and/or storability rather thancomfort. For example, a conventional mattress utilizing an array ofcoupled cells or springs provides an increasing resistance to deflectionwith deflection of the coupled cells or springs at a point of contactwith the user's body. The increasing resistance to deflection may causepressure points on the user's body (e.g., at a user's shoulders andhips) that protrude into the mattress more than other portions of theuser's body. Additionally, conventional foam mattresses may result indiscomfort for a user caused by excess compression or thermosetting.Further, conventional mattresses may be flammable or otherwise highlysusceptible to fire hazards.

SUMMARY

Implementations described and claimed herein address the foregoingproblems by providing a layered cushion comprising: a foam layer; a voidcell layer, wherein the foam layer substantially collapses at a lowerpressure than the void cell layer; a separation layer configured to beoriented between the foam layer and the void cell layer; and a coverconfigured to envelop the foam layer and the void cell layer. The coverconstrains the foam layer and the void cell layer in a selected positionand orientation when enveloping the foam layer and the void cell layer.The foam layer, the void cell layer, and the cover are removable fromone another.

Implementations described and claimed herein address the foregoingproblems by further providing a method of assembling a layered cushioncomprising: positioning a foam layer adjacent a first surface of aseparation layer and within a cover; positioning a void cell layeradjacent a second surface of the separation layer and within the cover,wherein the foam layer substantially collapses at a lower pressure thanthe void cell layer; and closing the cover to envelop the foam layer andthe void cell layer. The foam layer, the void cell layer, and the coverare removable from one another.

Implementations described and claimed herein address the foregoingproblems by still further providing a washable layered mattresscomprising: a fluid permeable foam layer; a fluid permeable void celllayer including a matrix of four or more void cells, wherein the foamlayer substantially collapses at a lower pressure than the void celllayer; a separation layer oriented between the foam layer and the voidcell layer; and a cover that envelops and constrains the foam layer andthe void cell layer in a selected position and orientation. The foamlayer, the void cell layer, and the cover are removable from oneanother.

Other implementations are also described and recited herein.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 illustrates a perspective cross-sectional view of an examplewashable layered mattress.

FIG. 2 illustrates an elevation cross-sectional view of an examplehelmet with a washable layered cushion therein.

FIG. 3 illustrates a partial cross-sectional view of an example layeredcushion.

FIG. 4 illustrates a perspective view of an example layered cushion in afully disassembled state.

FIG. 5 illustrates an elevation view of an example layered cushion withan open cover.

FIG. 6 illustrates an elevation view of an example layered cushion in anunloaded state.

FIG. 7 illustrates an elevation view of an example layered cushion in afirst partially loaded state.

FIG. 8 illustrates an elevation view of an example layered cushion in asecond partially loaded state.

FIG. 9 illustrates an elevation view of an example layered cushion in aheavily loaded state.

FIG. 10 illustrates an example pressure over deflection curve forcomponent and system response characteristics of an example layeredcushion.

FIG. 11 illustrates example operations for assembling a layered cushionaccording to the presently disclosed technology.

FIG. 12 illustrates example operations for cleaning a layered cushionaccording to the presently disclosed technology.

DETAILED DESCRIPTIONS

FIG. 1 illustrates a perspective cross-sectional view of an examplewashable layered mattress 100. The layered mattress 100 includes a foamlayer 102, a separation layer 126, a layer of void cells 104, astructure layer 106, and a cover 108. Details of each of the individualcomponent layers of the mattress 100 will be discussed in detail below.FIG. 1 is not drawn to scale.

The layered mattress 100 may sit atop a structural framework (not shown)that lifts the layered mattress 100 to a desirable height so that a user124 may sit and/or lie upon the mattress 100 to comfortably rest and/orsleep. The component layers of the mattress 100 are specificallyconfigured to be assembled and disassembled. This allows the individualcomponent layers of the mattress 100 to be replaced without replacingthe entire layered mattress 100. Further, each of the individualcomponent layers of the mattress 100 are fluid permeable to enable easycleaning of the layered mattress 100, either in an assembled ordisassembled state, using water and/or a solution of water and acleaning agent.

FIG. 2 illustrates an elevation cross-sectional view of an examplehelmet 201 with a washable layered cushion 200 therein. The layeredcushion 200 includes a foam layer 202, a separation layer 226, a layerof void cells 204, and a cover 208. Details of each of the individualcomponent layers of the layered cushion 200 will be discussed in detailbelow. FIG. 2 is not drawn to scale.

The layered cushion 200 may be inserted and secured within the helmet201 to comfortably cushion a user's head 224 from impacts. The componentlayers of the cushion 200 are specifically configured to be assembledand disassembled. This allows individual component layers of the cushion200 to be replaced without replacing the entire layered cushion 200.Further, each of the individual component layers of the cushion 200 arefluid permeable to enable easy cleaning of the layered cushion 200,either in an assembled or disassembled state, using water and/or asolution of water and a cleaning agent.

FIG. 3 illustrates a partial cross-sectional view of an example layeredcushion 300. The layered cushion 300 includes a foam layer 302 and alayer of void cells 304 with a separation layer 326 there between. Thelayered cushion 300 further includes a structure layer 306 and a cover308 that at least partially encompasses the other component layers ofthe cushion 300. Further, the layered cushion 300 may include more orfewer layers or components as described herein. A portion of the cover308 is missing to illustrate the component layers within the layeredcushion 300.

The individual layers of the layered cushion 300 may be arranged in anyorder or manner. In an implementation, the cover 308 couples the othercomponent layers together with the foam layer 302 providing, inconjunction with the cover 308, a user interface. The separation layer326 may lie between the foam layer 302 and the layer of void cells 304to prevent the foam layer 302 from collapsing into the individual cellsof the layer of void cells 304. The structure layer 306 is thebottom-most layer of the layered cushion 300. The layered cushion 300reduces pressure points and maximizes comfort while permitting thetransmission of fluids and particles through and out of each of theindividual layers for easy cleaning. Low pressure support provided bythe foam layer 302 and high pressure support provided by the layer ofvoid cells 304 creates a layered cushion 300 that contours to andsupports a user's body and that is soft and comfortable.

The foam layer 302 is porous and has low density that permits the easytransmission of fluids there through. The foam layer 302 is formed withrelatively few pores per inch, for example, 25 to 35 pores per inch tomaximize the hygienic characteristics (e.g., the capability to transmitsfluids there through) of the foam layer 302. The foam layer 302 may bemade of, for example, urethane, an organic (e.g., polyolefin) or aninorganic (e.g., silicone-based) polymer, rubber, or any other materialthat is conformable, resilient, and has a porous structure that allowsfluids and particles to move freely through the foam layer 302.

In one implementation, the foam layer 302 is a reticulated urethanefoam, which has a high tear strength, satisfactory elongation, andsatisfactory resiliency. Further, through thermal reticulation, the poresizes of the reticulated urethane foam may be increased. In anotherimplementation, the foam layer 302 may be a cushion with interconnectedpolymer extrusions wandering in a spaghetti-like or net pattern. Becausethe foam layer 302 is designed to permit the easy transmission of fluidsthere through, the foam layer 302 does not readily retain fluid or trapparticles. As such, the foam layer 302 may be thoroughly cleaned betweenuses.

Many porous, low density foams are susceptible to degradation andcombustion. Further, many such foams have low resistance to compressionset. Conversely, the foam layer 302 is optimized to fight compressionset, maximize durability, and minimize combustibility. The foam layer302 may be treated to make the foam material fire retardant or resistantto ignition from an open flame. For example, an intumescing coating maybe applied to the foam layer 302 to make it fire retardant.Alternatively or additionally, the foam layer 302 may be made from aninherently fire retardant reticulated urethane, which is treated withadditives at the compounding stage. Further, the low density range ofthe foam layer 302, for example, 2.2 to 3.0 pounds per cubic foot,increases the resistance to compression set, and the relatively lowpores per inch of the foam layer 302 permits fluid transmission throughthe foam layer 302. The resistance to compression set increases thedurability of the foam layer 302 and allows for repeated use andcleaning of the layered cushion 300. Many types of foam soften inreaction to body heat, which may result in thermosetting of the foam. Assuch, in designing the foam layer 302, the average temperature of ahuman body and/or expected storage, transportation, and usageenvironment temperatures are considered to prevent thermosetting of thefoam layer 302.

The foam layer 302 contours to the user's body to maximize comfort andinterface pressure reduction. The foam layer 302 contours and molds tothe shape of the user's body in reaction to the user's body heat andweight and returns to its original form once the pressure from theuser's body is removed from the foam layer 302. The firmness of the foamlayer 302 maximizes comfort and interface pressure reduction. Forexample, the foam layer 302 may be 2 inches thick with a 55 percentusable stroke, which represents the percentage of compression before thefoam densifies, and have a 25 to 35 indentation force deflection rating.

The layer of void cells 304 includes cushioning cells or support unitsextending from one or more substantially planar surfaces. The layer ofvoid cells 304 may be, for example, 3.2 inches thick with a 70 percentusable stroke. As a result, the layered cushion 300 has a high degree ofcompliance while being relatively compact. The cushioning cells (or voidcells) are hollow chambers that may create a relatively constant forceto resist deflection. In one implementation, the cushioning cells aretapered. Further, the cushioning cells may be hexagonal, hemispherical,hemiellipsoidal, conical, cubical, pyramidal, cylindrical, etc. However,other shapes configured to resist deflection due to compressive forcesare contemplated. The layer of void cells 304 is generally made frommaterials that are elastically deformable under expected load conditionsand will withstand numerous deformations without fracturing or otherwisedegrading. Example materials include thermoplastic urethane,thermoplastic elatomers, styrenic co-polymers, rubber, Dow Pellethane®,Lubrizol Estane®, Dupont™ Hytrel®, ATOFINA Pebax®, and Krayton polymers.

In one implementation, the layer of void cells 304 includes a topsubstantially planar surface opposing a bottom substantially planarsurface, each surface having one or more indentations forming cushioningcells. For example, the cushioning cells may have a 1.6 inches tallhemisphere with a 5-degree draft angle. The top surface links thecushioning cells extending from the top surface together, and the bottomsurface links the cushioning cells extending from the bottom surfacetogether. The cushioning cells extending from a given surface may beindividually attached to that surface and not to each other. In thealternative, the cushioning cells may extend from a given surface andfurther attach to neighboring cushioning cells. A cushioning cellextending from the top surface meets an opposing cushioning cellextending from the bottom surface at a connection interface. Theconnection interface may be perforated to allow for the transmission offluids through each of the cushioning cells in the layer of void cells304. Additionally, the surface area of the top and bottom surfacescorresponding to each cushioning cell may be open to further permit thetransmission of fluids through the layer of void cells 304. The opensurfaces and perforations facilitate cleaning of the layer of void cells304.

In another implementation, the individual cushioning cells are arrangedin a top matrix and a bottom matrix. The top matrix extends from a topsurface of a central binding layer, and the bottom matrix extends from abottom surface of the central binding layer. In one implementation, thecushioning cells are filled with ambient air and closed or sealed toprevent fluids or particles from penetrating or becoming trapped. Inanother implementation, the cushioning cells are un-filled. Further,there may be one or more holes in the cushioning cells and/or centralbinding layer through which air or fluid may pass freely when thecushioning cells are compressed and de-compressed and/or to facilitatecleaning. In yet another implementation, the cushioning cells are filledwith a foam or a fluid other than air. The foam or certain fluids may beused to insulate a user's body, facilitate heat transfer from the user'sbody to/from the layered cushion 300, and/or affect the resistance todeflection of the layered cushion 300.

In an implementation utilizing a central binding layer (not shown), thecushioning cells may compress independently of one another, within anindependent deformation range to reduce the potential for pressurepoints on the user's body. The cushioning cells individually compress todistribute the weight of the user evenly. At least the material, wallthickness, size, and shape of each of the cushioning cells define theresistive force each of the cushioning cells can apply. For example, thelayer of void cells 304 may have a 0.95 pounds per square inchactivation or buckling load and a 0.78 pounds per square inch supportforce in the active deflection range. This allows the layer of voidcells 304 to conform to the user's body with an even force on the user'sbody to maximize comfort and reduce the potential for pressure points onthe user's body. For example, the layer of void cells 304 has asufficient firmness to support a larger user (e.g., a user with a bodyweight greater than the 75th percentile) but also is capable ofdeforming and contouring to the body of a smaller user (e.g., a userwith a body weight less than the 25th percentile). In anotherimplementation, the layer of void cells 304 is a honeycomb structure.

Further, the layered cushion 300 achieves an optimal SAG factor, whichrepresents the ratio of firmness between a foam layer and a secondarylayer. For example, the layered cushion 300 may have a SAG factor ofapproximately 2 between the foam layer 302 and the layer of void cells304, which is optimal for pressure ulcer prevention.

In still another implementation, the cushioning cells are arranged in atop matrix that extends from a top binding layer and a bottom matrixthat extends from a bottom binding layer. The void cells that extendfrom the top binding layer meet the bottom binding layer and the voidcells that extend from the bottom binding layer meet the top bindinglayer in an interdigitated manner. The interdigitated layer of voidcells may be perforated where each cushioning cell meets the oppositebinding layer to facilitate cleaning and allow the transmission offluids there through.

The structure layer 306 provides system firmness and rigidity to thelayered cushion 300 to maximize comfort and portability of the layeredcushion 300. The structure layer 306 is planar and substantially rigid.The structure layer 306 evens the surface the layered cushion 300 isplaced upon to maximize comfort to a user. Some implementations will notinclude the structure layer 306. The structure layer 306 may be madefrom any rigid material that does not retain fluids and that may beeasily cleaned. For example, the structure layer 306 may be made of aplastic thermoplastic urethane. However, other materials including butnot limited to metals, plastics, ceramics, and rubbers are contemplatedto make the structure layer 306.

The cover 308 couples the layers, including the foam layer 302, thelayer of void cells 304, and the structure layer 306, together in adesired position and orientation to form the layered cushion 300 andprevents the component layers from deteriorating as a result of exposureto contaminants and/or environmental factors. The cover 308 may beremovable to facilitate cleaning of the component layers separately andthe cover 308 may be machine washable. Further, the cover 308 may beinherently fire retardant as a result of the material makeup, coating,etc. For example, the cover 308 may be made from a blend of syntheticand natural fibers including but not limited to Dupont™ Nomex®, cotton,nylon, and other aramid fibers. In an implementation, the cover 308 andthe separation layer 326 together includes a divider pocket to separatethe foam layer 302 from the layer of void cells 304 and to providefurther structure to the layered cushion 300 and to prevent the foamlayer 302 from collapsing into the layer of void cells 304.

FIG. 4 illustrates a perspective view of an example layered cushion 400in a fully disassembled state. The layered cushion 400 may bedisassembled into individual component layers, a cover 408, a layer ofvoid cells 404, a foam layer 402, and a structure layer 406, tofacilitate storage or cleaning Further, each individual component layermay be treated with anti-microbial substance and/or be made of ananti-microbial material.

In one implementation, each individual component layer may be replacedand recycled without replacement of other component layers. For example,the layer of void cells 404 and the structure layer 406 may be recycledinto and/or reused as a new layer of void cells and a new structurelayer, respectively. Further, the cover 408 and the foam layer 402 maybe recycled into a new cover and foam layer, respectively, and/or reusedfor other products. Because the layered cushion 400 may be recycled andis easy to clean, the layered cushion 400 may be reused in a variety ofenvironments, such as camping or military applications. Additionally,because the layered cushion 400 is hygienic and may be easily cleaned,the layered cushion 400 may be hygienically used by multiple users.

The cover 408 couples the component layers of the layered cushion 400together in a desired position and orientation. The cover 408 isremovable so that the component layers may be separated to facilitatecleaning (e.g., via opening a hook-and-loop fastener 440 oriented alongone side of the cover 408). The cover 408 may slip onto and/or wraparound the layers and it made include one or more other selectivelydetachable fasteners (e.g., hook-and-loop fasteners, buttons, snaps,etc.) to allow for easy removal. The cover 408 may also be machinewashable or cleaned by other methods.

The layer of void cells 404 includes two opposing surfaces with one ormore open cells extending from each surface. Each open cell meets anopposing open cell at a connection interface. The connection interfaceis perforated to facilitate cleaning. Fluids, such as water or cleaningagents, or air may be forced from the openings in the surfacescorrelating to the open cells through the perforations in eachconnection interface to flush out contaminates. Fluids or air may beintroduced at one surface of the layer of void cells 404 and flushedthrough the perforations in each connection interface to the oppositesurface to remove particles or contaminates.

The foam layer 402 permits fluids to move freely there through. Fluidsand/or cleaning agents may be flushed from one end or side of the foamlayer 402 to the opposite end or side to remove particles orcontaminates from the foam layer 402. Further, because the foam layer402 does not retain fluids, the time required for the foam layer 402 todry is reduced as compared to other foams, which prevents molds or othermoisture born contaminants from emerging in the foam layer 402. Thestructure layer 406 is rigid and does not retain fluids. The structurelayer 406 may be easily cleaned by rinsing the structure layer 406 withfluids, such as water or cleaning agents.

FIG. 5 illustrates an elevation view of an example layered cushion 500with an open cover 508. The layered cushion 500 includes the cover 508,a foam layer 502, a layer of void cells 504, and a structure layer 506.The cover 508 couples the individual component layers of the layeredcushion 500 together in a desired position and orientation and preventsthe individual component layers from deteriorating (e.g., by exposure toenvironmental elements). The layered cushion 500 further includes aseparation layer 526 to separate the foam layer 502 from the layer ofvoid cells 504 and to provide further structure to the layered cushion500 and prevent the foam layer 502 from collapsing into the layer ofvoid cells 504.

In one implementation, the cover 508 and the separation layer 526together form a pocket. The foam layer 502 is inserted into the pocketand provides a comfortable interface for a user. The foam layer 502 isoptimized to fight compression, maximize comfort, and maximizedurability, permitting multiple uses. The foam layer 502 contours to theuser's body to maximize comfort and reduce pressure points on the user'sbody. Further, the foam layer 502 contours and molds to the shape of theuser's body in reaction to the user's body heat and/or weight andreturns to its original shape once pressure from the user's body isremoved from the layered cushion 500.

The layer of void cells 504 is disposed between the foam layer 502 andthe structure layer 506. The layer of void cells 504 includes a topsubstantially planar surface 512 and an opposing bottom substantiallyplanar surface 510, each surface having one or more tapered cushioningcells (e.g., cushioning cells 514 and 516) protruding there from. Thecushioning cells are tapered hollow chambers that create a relativelyconstant force to resist deflection. While the cushioning cells depictedin FIG. 5 are generally truncated square pyramids in shape, thecushioning cells may be hemispherical, hemiellipsoidal, conical,cubical, pyramidal, cylindrical, or any other shape capable of having ahollow interior volume.

The top surface 512 links the cushioning cells extending from the topsurface together, and the bottom surface 510 links the cushioning cellsextending from the bottom surface together. Each cushioning cellextending from the top surface meets an opposing cushioning cellextending from the bottom surface at a connection interface. Forexample, cushioning cell 514 extends from the top surface 512 to meetopposing cushioning cell 516 extending from the bottom surface 510 at aconnection interface 518. The connection interfaces are perforated(i.e., they have one or more holes passing there through) to allow forthe transmission of fluids through each of the cushioning cells in thelayer of void cells 504. Additionally, the surface area of the top andbottom surfaces 512 and 510 respectively corresponding to eachcushioning cell is open to further permit the transmission of fluidsthrough the layer of cushioning cells 504. The structure layer 520 is atthe bottom within the cover 508 and provides rigidity to the layeredcushion 500. The structure layer 520 is substantially planar and rigidand evens the surface the layered cushion 500 is placed upon to maximizecomfort to the user.

FIG. 6 illustrates an elevation view of an example layered cushion 600in an unloaded state. The layered cushion 600 includes a foam layer 602,a top matrix of void cells 628, and a bottom matrix of void cells 630.Both matrices of void cells 628, 630 collectively form a layer of voidcells 604 as discussed in detail herein. The foam layer 602 is a porousand low-density foam, for example, a reticulated foam. The foam layer602 has a resistance to compression set and contours to a surfaceapplying a load or pressure without thermosetting. The layered cushion600 excludes a cover for illustration purposes (to allow the foam layer602 and the layer of void cells 604 to be viewed without obstruction).

The layered cushion 600 is placed in a compression test apparatus 620,which includes a top surface 632 and a bottom surface 634. The layeredcushion 600 is placed between the top surface 632 and the bottom surface634 of the compression test apparatus 620. Compression is applied to thelayered cushion 600 via the compression test apparatus 620. In theimplementation of FIG. 6, no compressive force is applied to the layeredcushion 600.

The top matrix of void cells 628 includes a top planar layer 612 ofcushioning cells (e.g., cushioning cell 614) extending from the topplanar layer 612. The bottom matrix of void cells 630 includes a bottomplanar layer 610 of cushioning cells (e.g., cushioning cell 616)extending from the bottom planar layer 610. Each cushioning cellextending from the top planar layer 612 meets an opposing cushioningcell extending from the bottom planar layer 610 at a connectioninterface. For example, the cushioning cell 614 extends from the topplanar layer 612 to meet the opposing cushioning cell 616 extending fromthe bottom planar layer 610 at a connection interface 618.

In one implementation, the cushioning cells in the top matrix of voidcells 628 and the bottom matrix of void cells 630 each have a thicknessthat varies over a height of the cushioning cell. For example, where thecushioning cell 614 nears the top planar layer 612, the wall thicknessof the cushioning cell 614 may be greater than where the cushioning cell614 nears the connection interface 618, or visa versa. Varying thethickness of the cushioning cells over their height may be used to yielda changing resistive force depending upon the amount of compression ofthe cushioning cells (i.e., yielding a positive and/or increasing springrate). Additionally, the top matrix of void cells 628 may be a differentthickness than the bottom matrix of void cells 630.

FIG. 7 illustrates an elevation view of an example layered cushion 700in a first partially loaded state. The layered cushion 700 includes afoam layer 702, a top matrix of void cells 728, and a bottom matrix ofvoid cells 730. Both matrices of void cells 728, 730 collectively form alayer of void cells 704 as discussed in detail herein. The foam layer702 is a porous and low-density foam, for example, a reticulated foam.The foam layer 702 has a resistance to compression and contours to asurface applying a load without thermosetting. The layered cushion 700excludes a cover for illustration purposes (to allow the foam layer 702and the layer of void cells 704 to be viewed without obstruction).

The top matrix of void cells 728 and the bottom matrix of void cells 730include cushioning cells (e.g., cushioning cells 714 and 716). Eachcushioning cell meets an opposing cushioning cell at a connectioninterface. For example, the cushioning cell 714 meets the cushioningcell 716 at a connection interface 718. The cushioning cells deform andcompress as a load is applied to one or more of the void cells.

The layered cushion 700 is placed in a compression test apparatus 720,which includes a top surface 732 and a bottom surface 734. The layeredcushion 700 is placed between the top surface 732 and the bottom surface734 of the compression test apparatus 720. A load (e.g., 19.0 lb) isapplied to the layered cushion 700 via the compression test apparatus720. The foam layer 702 compresses before the top matrix of void cells728 and the bottom matrix of void cells 730 begin to compress. The foamlayer 702 contours to the shape of the top matrix of void cells 728 andbegins to collapse into the cushioning cells in the top matrix of voidcells 728. Because the load in the testing apparatus 720 is applied tothe foam layer 702 evenly, the foam layer 702 evenly compresses. Theload is insufficient to compress the cushioning cells in the top matrixof void cells 728 or bottom matrix of void cells 730. For example,cushioning cells 714 and 716 are not compressed. In anotherimplementation, when the layered cushion 700 includes a separation layerbetween the foam layer 702 and the layer of void cells 704, the foamlayer 702 is prevented from contouring to or collapsing into thecushioning cells in the top matrix of void cells 728.

FIG. 8 illustrates an elevation view of an example layered cushion 800in a second partially loaded state. The layered cushion 800 includes afoam layer 802, a top matrix of void cells 828, and a bottom matrix ofvoid cells 830. Both matrices of void cells 828, 830 collectively form alayer of void cells 804 as discussed in detail herein. The foam layer802 is a porous and low-density foam, for example, a reticulated foam.The foam layer 802 has an resistance to compression and contours to asurface applying a load without thermosetting. The layered cushion 800excludes a cover for illustration purposes (to allow the foam layer 802and the layer of void cells 804 to be viewed without obstruction).

The top matrix of void cells 828 and the bottom matrix of void cells 830include cushioning cells (e.g., cushioning cells 814 and 816). Eachcushioning cell meets an opposing cushioning cell at a connectioninterface. For example, the cushioning cell 814 meets opposing thecushioning cell 816 at a connection interface 818. The cushioning cellsdeform and compress as a load is applied to one or more of the voidcells.

The layered cushion 800 is placed in a compression test apparatus 820,which includes a top surface 832 and a bottom surface 834. The layeredcushion 800 is placed between the top surface 832 and the bottom surface834 of the compression test apparatus 820. A load (e.g., 23.3 lb) isapplied to the layered cushion 800 via the compression test apparatus820.

The testing apparatus 820 is applying a greater force than the testapparatus 720 of FIG. 7, and is compressing the layered cushion 800further. The foam layer 802 compresses before the top matrix of voidcells 828 and the bottom matrix of void cells 830 begin to collapse. Thefoam layer 802 contours to the shape of the top matrix of void cells 828and collapses into and around the cushioning cells in the top matrix ofvoid cells 828. Because the load in the testing apparatus 820 is appliedto the foam layer 802 evenly, the foam layer 802 evenly compresses.

The top matrix of void cells 828 and bottom matrix of void cells 830each collapse to create a relatively constant force to resistdeflection. For example, the cushioning cells 808 and 812 in combinationwith the foam layer 802 individually compress and conform to a user'sbody with an even force on the user's body to maximize comfort andreduce the potential for pressure points on the user's body. In anotherimplementation, when the layered cushion 800 includes a separation layerbetween the foam layer 802 and the layer of void cells 804, the foamlayer 802 is prevented from contouring to or collapsing into thecushioning cells in the top matrix of void cells 828.

In various implementations, the top matrix of void cells 828 has a lowerresistance to deflection and thus collapses before the bottom matrix ofvoid cells 830, which has a higher resistance to deflection. However, inother implementations, the bottom matrix of void cells 830 has a lowerresistance to deflection and thus collapses before the top matrix ofvoid cells 828. In yet other implementations, the top matrix of voidcells 828 and the bottom matrix of void cells 830 have the same orsimilar resistance to deflection and thus collapse simultaneously ornearly simultaneously.

FIG. 9 illustrates an elevation view of example layered cushion 900 in athird heavily loaded state. The layered cushion 900 includes a foamlayer 902 and a layer of void cells 904. The layer of void cells 904 isarranged in a top matrix and a bottom matrix, which areindistinguishable in the heavily loaded state depicted in FIG. 9. Thelayer of void cells 904 includes multiple cushioning cells that deformand compress as a load is applied to the layer of void cells 904.

The foam layer 902 is a porous and low-density foam, for example, areticulated foam. The foam layer 902 has a resistance to compression andcontours to a surface applying a load without thermosetting. The layeredcushion 900 excludes a cover for illustration purposes (to allow thefoam layer 902 and the layer of void cells 904 to be viewed withoutobstruction).

The layered cushion 900 is placed in a compression test apparatus 920,which includes a top surface 932 and a bottom surface 934. The layeredcushion 900 is placed between the top surface 932 and the bottom surface934 of the compression test apparatus 920. A load (e.g., 35.8 lb) isapplied to the layered cushion 900 via the compression test apparatus920.

The testing apparatus is applying a greater force than the testapparatus 914 of FIG. 8, and is compressing the layered sleep systemcomponents 900 further. The foam layer 902 compresses before the layerof void cells 904 collapses. The foam layer 902 contours to the shape ofthe layer of void cells 904 and collapses into and around the cushioningcells in the layer of void cells 904. Because the load in the testingapparatus 920 is applied to the foam layer 902 evenly, the foam layer902 evenly compresses. Further, the layer of void cells 904 is almostfully collapsed and the individual void cells are no longerdistinguishable from one another.

FIG. 10 illustrates an example pressure over deflection curve 1000 forcomponent and system response characteristics of an example layeredcushion. The graph 1000 illustrates the relationship between pressure(in pounds per square inch) and deflection (in inches) of a 2 inch foamlayer (1051), a 4 inch layer of void cells (1052), and a layered cushionsystem including both the 2 inch foam layer and the 4 inch layer of voidcells (1053).

The graph 1000 illustrates a difference in activation and supportpressure between the three curves. The 2-inch foam layer has an initialyield point 1036 that provides lower pressure support to a user's body.The lower pressure support of the 2-inch foam layer maximizes comfortand interface pressure reduction. The layer of void cells has a higherinitial yield point 1038, which provides displacement under higherloads, which in turn provides support for larger and/or more protrudingfeatures of the user's body (e.g., the user's shoulders or hips).

The layered cushion system including both the 2-inch foam layercomponent and the layer of void cells component combines the low andhigh-pressure support advantages of the 2-inch foam layer and the layerof void cells. As a result, curve 1053 does not have a distinct initialyield point and overall has a smoother pressure-deflection profile thancurves 1051 and 1052. Accordingly, the layered cushion system combinesthe low and high pressure support of the 2-inch foam layer component andthe layer of void cells component to provide a layered cushion thatcontours to and supports the user's body and that is soft andcomfortable to the user.

FIG. 11 illustrates example operations 1100 for assembling a layeredcushion according to the presently disclosed technology. A firstpositioning operation 1110 positions a foam layer within a pocket of alayered cushion cover. In one implementation, the foam layer is made ofa fluid permeable foam with a pore size large enough to facilitatetransmission of fluids through the foam layer with relative ease. Thefoam layer collapses under a load and provides a user a comfortableinterface with the layered cushion. In one implementation, the layeredcushion cover is made of a permeable flexible material (e.g., fabric ormesh). Further, the pocket may be formed contiguously with the layeredcushion cover and made of the same material as the layered cushioncover.

A second positioning operation 1120 positions a void cell layer adjacentthe foam layer within the layered cushion cover with a separation layerthere between. The void cell layer includes multiple cushioning cells orsupport units extending from one or more substantially planar surfaces.The individual cushioning cells collapse under a load, and the void celllayer collapses under a relatively greater load than the foam layer.This provides the user additional support. The separation layer may beformed contiguously with the layered cushion cover and made of the samematerial as the layered cushion cover or it may be a separate structureattached to the layered cushion cover. Further, the separation layer maybe the interior portion of the aforementioned pocket.

A third positioning operation 1130 positions a rigid layer adjacent thevoid cell layer, away from the foam layer, and within the layeredcushion cover. The rigid layer provides a structural foundation for thelayered cushion and may be made of any rigid material (e.g., wood,plastic, metal). In some implementations, a separate pocket within thelayered cushion cover receives the rigid layer. In otherimplementations, no rigid layer is included in the layered cushionbecause the layered cushion is intended to be placed on a rigid surface.

A closing operation 1140 closes the layered cushion cover around thefoam layer, the void cell layer, and the rigid layer. This envelops andsecures the layers in a desired position and orientation within thelayered cushion cover. In one implementation, the layered cushion coveris equipped with selective fasteners (e.g., hook-and-loop, buttons,snaps, etc.) oriented along at least 1 side of the layered cushioncover. The layers are inserted through the open side(s) of the layeredcushion cover and the layered cushion cover is selectively closed aroundthe layers.

FIG. 12 illustrates example operations 1200 for cleaning a layeredcushion according to the presently disclosed technology. An openingoperation 1210 opens the layered cushion cover to reveal an envelopedfoam layer, void cell layer, and rigid layer within the layered cushioncover. In one implementation, the opening operation 1210 is accomplishedby selectively detaching selective fasteners (e.g., hook-and-loop,buttons, snaps, etc.) oriented along at least 1 side of the layeredcushion cover.

A removing operation 1220 removes the foam layer, the void cell layer,and the rigid layer from the layered cushion cover. In one exampleimplementation, the removing operation 1220 may be performed by merelyphysically pulling each of the foam layer, the void cell layer, and therigid layer from the layered cushion cover. A flushing operation 1230flushes one or more of the foam layer, the void cell layer, the rigidlayer, and the cover with a cleansing fluid. The cleansing fluid mayinclude water and one or more cleansing and/or anti-microbial agents(e.g., soaps and chemicals) to facilitate cleansing of the layeredcushion. More specifically, the cleansing fluid may pass over andthrough holes and/or pores in the foam layer, the void cell layer, therigid layer, and/or the cover to flush contaminants from the foam layer,the void cell layer, the rigid layer, and/or the cover.

A drying operation 1240 dries the foam layer, the void cell layer, therigid layer, and/or the cover. The drying operation 1240 may beperformed on one or more of the layers that was flushed in the flushingoperation 1230. The drying operation 1240 further may be performedmerely by ambient temperature evaporation or by the application of heatand/or forced air to the foam layer, the void cell layer, the rigidlayer, and/or the cover to facilitate the evaporation. A reassemblingoperation 1250 reassembles the foam layer, the void cell layer, therigid layer, and/or the cover. In one implementation, the reassemblingoperation 1250 may be performed using the operations 1100 of FIG. 11.

The logical operations making up the embodiments of the inventiondescribed herein are referred to variously as operations, steps,objects, or modules. Furthermore, it should be understood that logicaloperations may be performed in any order, adding and/or omitting stepsas desired, unless explicitly claimed otherwise or a specific order isinherently necessitated by the claim language.

The above specification, examples, and data provide a completedescription of the structure and use of exemplary embodiments of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended. Furthermore, structuralfeatures of the different embodiments may be combined in yet otherembodiments without departing from the recited claims.

What is claimed is:
 1. A layered cushion comprising: a foam layer; avoid cell layer, wherein the foam layer substantially collapses at alower pressure than the void cell layer; a separation layer configuredto be oriented between the foam layer and the void cell layer; and acover configured to envelop the foam layer and the void cell layer,wherein the cover constrains the foam layer and the void cell layer in aselected position and orientation when enveloping the foam layer and thevoid cell layer, and wherein the foam layer, the void cell layer, andthe cover are removable from one another.
 2. The layered cushion ofclaim 1, further comprising: a rigid layer configured to be orientedadjacent the void cell layer, wherein the cover is further configured toenvelop the rigid layer; the cover further constrains the rigid layer ina selected position and orientation when enveloping the foam layer, thevoid cell layer, and the rigid layer; and the rigid layer is removablefrom the foam layer, the void cell layer, and the cover.
 3. The layeredcushion of claim 1, wherein the separation layer adjoins the cover. 4.The layered cushion of claim 1, wherein the foam layer, the void celllayer, and the cover are fluid permeable.
 5. The layered cushion ofclaim 1, wherein at least one void cell in the void cell layer includesa drainage hole.
 6. The layered cushion of claim 1, wherein acombination of the foam layer and the void cell layer provides asubstantially monotonic pressure-deflection curve.
 7. The layeredcushion of claim 1, wherein the void cell layer includes four or morevoid cells arranged in a matrix.
 8. The layered cushion of claim 1,wherein the void cell layer include two layers of void cells in anopposing or interdigitated arrangement.
 9. The layered cushion of claim1, wherein the cover includes one or more selectively detachablefasteners oriented along at least one side of the cover.
 10. A method ofassembling a layered cushion comprising: positioning a foam layeradjacent a first surface of a separation layer and within a cover;positioning a void cell layer adjacent a second surface of theseparation layer and within the cover, wherein the foam layersubstantially collapses at a lower pressure than the void cell layer;and closing the cover to envelop the foam layer and the void cell layer,wherein the foam layer, the void cell layer, and the cover are removablefrom one another.
 11. The method of claim 10, further comprising:positioning a rigid layer adjacent the void cell layer prior to theclosing operation, wherein the closing operation further envelops therigid layer and the rigid layer is removable from the foam layer, thevoid cell layer, and the cover.
 12. The method of claim 10, wherein theseparation layer adjoins the cover.
 13. The method of claim 10, whereinthe foam layer, the void cell layer, and the cover are fluid permeable.14. The method of claim 10, wherein at least one void cell in the voidcell layer includes a drainage hole.
 15. The method of claim 10, whereina combination of the foam layer and the void cell layer provides asubstantially monotonic pressure-deflection curve.
 16. The method ofclaim 10, wherein the void cell layer includes four or more void cellsarranged in a matrix.
 17. The method of claim 10, wherein the void celllayer include two layers of void cells in an opposing or interdigitatedarrangement.
 18. The method of claim 10, wherein the cover includes oneor more selectively detachable fasteners oriented along at least oneside of the cover.
 19. A washable layered mattress comprising: a fluidpermeable foam layer; a fluid permeable void cell layer including amatrix of four or more void cells; a separation layer oriented betweenthe foam layer and the void cell layer; and a cover that envelops andconstrains the foam layer and the void cell layer in a selected positionand orientation, wherein the foam layer, the void cell layer, and thecover are removable from one another.
 20. The washable layered mattressof claim 19, wherein the foam layer substantially collapses at a lowerpressure than the void cell layer.